#ifdef GL_ES
#extension GL_OES_texture_3D : enable
precision mediump int;
precision mediump float;
precision mediump sampler3D;
#endif

#define USE_OGRE_FROM_FUTURE
#include <OgreUnifiedShader.h>

SAMPLER2D(RT, 0);
SAMPLER3D(noiseVol, 1);

OGRE_UNIFORMS(
uniform vec4 lum;
uniform float time;
)

MAIN_PARAMETERS
IN(vec2 oUv0, TEXCOORD0)
MAIN_DECLARATION
{
  vec4 oC;
	oC = texture2D(RT, oUv0);
	
	//obtain luminence value
	oC = vec4_splat(dot(oC, lum));
	
	//add some random noise
	oC += vec4_splat(0.2) * (texture3D(noiseVol, vec3(oUv0 * vec2_splat(5.0), time))) - vec4_splat(0.05);
	
	//add lens circle effect
	//(could be optimised by using texture)
	float dist = distance(oUv0, vec2(0.5, 0.5));
	oC *= vec4_splat(smoothstep(0.5, 0.45, dist));
	
	//add rb to the brightest pixels
	oC.rb = vec2(max(oC.r - 0.75, 0.0) * vec2_splat(4.0));
  
	gl_FragColor = oC;
}